China Eastern Airlines admitted yesterday that some pilots at its Yunnan branch last week "deliberately" turned back midway through their flights - ostensibly because of poor weather - in a rare strike action demanding higher pay.

The pilots involved have been suspended from work as an internal investigation as well as a probe by the Civil Aviation Administration of China (CAAC) continue.

Two senior officials of the Yunnan branch have been sacked, and a deputy general manager of the parent airline has been appointed as the new branch head to check why 21 flights returned to Kunming last Monday and Tuesday, according to a statement released by China Eastern yesterday.

"We will punish those pilots in line with company rules and relevant regulations once the investigation concludes," it said.

A CAAC spokesperson said yesterday that the investigation team it sent to Yunnan over the weekend had concluded that the weather in the province last Monday was suitable for flying.

The CAAC has ordered China Eastern to suspend the cockpit crew of the flights involved; and said it would also look into the responsibility of the airline's management.

China Eastern said it had compensated some of the passengers who returned to Kunming; and promised to compensate all passengers affected.

The pilots reportedly took the extreme step because their complaints about overtime and long night shifts were not satisfactorily addressed, and they earn much less than their counterparts at the parent company.

"The salaries of pilots flying between major cities and short-haul feeder routes are totally different. The pilots in the Yunnan branch earn much less than those flying trunk routes," said Zheng Qingping, an analyst at Tebon Securities.

The Yunnan branch's routes include many popular tourist destinations such as the mountain towns of Dali and Lijiang.

China Eastern said in a statement on Saturday that the flight returns were mainly caused by poor weather conditions.

But most passengers were not satisfied with the explanation.

An official with the Central Meteorological Observatory rejected the "poor weather" claim when interviewed by CCTV.

The weather in Lijiang and Dali on March 31 was good for take-offs and landings, and all flights of other airlines operated normally, he said.

Before the China Eastern incident, about 40 pilots with Shanghai Airlines asked for sick leave on March 14. And on March 28, 11 pilots with Wuhan-based East Star Airlines also applied for sick leave.